Add .git-blame-ignore-revs

Because Intellij will error out if we set git config to use this file
and it does not exist, and we do need to set git config to use this file
for the main branch, at least.

Author: yrodiere

.git-blame-ignore-revs

@@ -51,6 +51,7 @@ GitHub there are a few pre-requisite steps to follow:
 the linked page, this also includes:
     * [set up your local git install](https://help.github.com/articles/set-up-git) 
     * clone your fork
+* Instruct git to ignore certain commits when using `git blame`. From the directory of your local clone, run this: `git config blame.ignoreRevsFile .git-blame-ignore-revs`
 * See the wiki pages for setting up your IDE, whether you use 
 [IntelliJ IDEA](https://hibernate.org/community/contribute/intellij-idea/)
 or [Eclipse](https://hibernate.org/community/contribute/eclipse-ide/)<sup>(1)</sup>.